Inspired by and based on madeofteeth's Umbral Valkyr Prime Build...

I just added some optimizations and alternatives. HUGE THANKS to teeth; I learned a lot after discovering and playing around with their build.

We get the same stats, same Augur Secrets flex-slot, maxed out [Preparation], a flexible Exilus slot BUT we don't have to use an Umbra Forma. A big hooray for Forma Peasants like me!

THE BUILD

A non-meta friendly setup for Hysteria. We won't be using ANY defensive mods since we're aiming to use Hysteria every single second in combat. We're juggling Ability Efficiency and Duration for build variety in Helminth subsumed abilities. I personally recommend Fire Blast for armor stripping as a preference over Pillage since the range is instantly 19.8m and we don't have enough Ability Strength to strip shields in one cast of Pillage; Fire Blast does not scale with high Ability Strength, so it always full-strips after two casts as long as it's on positive Strength. On top of that, we have a guaranteed Heat proc from it which reduces armor by 50% temporarily if you decide to cast Fire Blast just once and a nice boost for [Condition Overload]...AND mild CC from the blast!

ARCHON SHARDS

Crimson Shards with +Melee Critical Damage are the best for [Valkyr]'s Hysteria. +Ability Strength is only a good option if you use something like Eclipse or Roar

ALTERNATIVES AND ADJUSTMENTS

1. Maxing out Ability Efficiency at the cost of Ability Duration: (for players who want to keep vanilla [Valkyr] abilities or just want efficiency)
   a. drop [Primed Continuity] from the innate (V) Madurai Slot
   b. put Augur Secrets on the innate (V) Madurai Slot
   c. put Streamline on the unpolarized slot
   d. R4/R5 Fleeting Expertise, doesn't matter which one you have/use...[Eternal War] will keep your Warcry up as long as you keep killing :)

2. [Preparation] replaces [Coaction Drift]: like in the OG build, this lets you start out with full energy every time. But you do need another Forma

3. Arcane Strike should be your go-to if you don't have Arcane Energize, Molt Augmented if you run high Ability Strength with Roar or Eclipse

4. MOAR UMBRA! (I don't recommend this since Hysteria-claws-mode is literal invulnerability but you do you)
   a. want to slap on a second Umbra mod but still without using an Umbra Forma? just use regular Forma on every other slot BUT you will be stuck using Exilus mods with 10 base drain or less (the Exilus slot must also have a Forma so it will be 5 drain or less)...replace [Augur Secrets] with your [Umbral Vitality] >>>>> results in -13 Ability Strength but you get 850 max hp
   b. want all three Umbra? you'll need to do everything above, use Exilus drain 8 or less, replace [Continuity] with your Umbra, and this time...one Umbra forma is necessary :') >>>>> results in a spicy +10 Ability Strength, 1070hp, 2047 armor

5. [Power Drift] replaces [Coaction Drift]?: they're interchangeable but Coaction gives marginally more damage as long as you're using [Steel Charge], I'd say swap to [Power Drift] if you actively use abilities other than [Valkyr]'s 2 and 4 or if you like to shift out of Hysteria often and don't want to chance being knocked down by Eximus (thanks to Gough-dough for shedding light on this :D)

6. Arcane Strike or Molt [Vigor] replaces Arcane Energize: for those who don't have Arcane Energize (take note that you will need to resort to other methods for Hysteria upkeep)

MANAGING ENERGY WITHOUT HIGH-RANK ARCANE ENERGIZE

Arcane Energize is one of the most coveted and expensive Arcanes out there. Simply because it's the top choice for energy economy comfort...especially for an energy-hungry Valkitty

Here are some of the "workarounds" that I know of:

1. Spend one more Forma and replace [Augur Secrets] with [Equilibrium]. Then, use a companion (preferably a [Panzer Vulpaphyla] for its immortality) with [Synth Fiber]. This allows you to pick up Health Orbs (which restore energy thanks to [Equilibrium]) at full health!
2. Squad Energy Restore gear item (only works when Hysteria is OFF)
3. Emergence Dissipate Operator Arcane <<<<- somewhat of a good alternative to Arcane Energize but requires grouped enemies
4. Dethcube sentinel with Energy Generator <<<<- synergizes well with Energy Conversion and is more passive in gameplay (might die tho)
5. Zenurik School Wellspring (only works when Hysteria is OFF) <<<<- it's not too hard to manage but you need to time your Hysteria activations

[Energy Siphon] will not work while Hysteria is active; better stick to [Corrosive Projection] or [Steel Charge]
Plenty of good [Dethcube] builds out there, I personally use aestheticphonetic's Dethcube Prime

MISC NOTES

I am in no way claiming that this is Valkyr meta; just a build I would like to make with respect to teeth's build
I am in no way one-upping the other builds; this is a community for Tenno to have fun and share builds and I abide by that
Please write criticisms with respect; I am eager to learn more and read feedback, but I don't bother responding kindly to toxicity
Many thanks to the original author(s) of the build(s) I mentioned...and to YOU for checking this out :)

MY THOUGHTS

Just my opinions, nothing important:

• So, why do I favor their build over the other ones? This is because teeth's build has the nice balance between Ability Efficiency and Ability Duration. Most of the other builds maximize Ability Duration to benefit subsumed buff abilities while minimizing Hysteria drain; these may limit you to use buff-focused subsumed abilities only.
• Having energy efficiency in the mix allows [Valkyr]'s playstyle to be more flexible to using abilities like Breach Surge or Fire Blast for armor stripping, or niche abilities that are fire-and-forget
• Min-maxing Ability Duration over Ability Efficiency can also limit newer players who do not have maxed out Arcane Energize to be able to keep Hysteria up all the time (i.e. having to deactivate/activate Hysteria occasionally for energy economy)